Bulldozer and bucket



06%. 17, J. A HAYNES BULLDOZER AND BUCKET 2 Sheets-Sheet 1 Filed April7, 1965 [N VEN TOR. Hgg/Yes Jo/W? A BY /Mf Affarmggs 1957 J. A. HAYNESBULLDOZER AND BUCKET 2 Sheets-Sheet 2 Filed April 7. 1965 INVENTOR. JohnA. Hgz nes BY ,MYLM

A f forwggs United States Patent ()fifice 3,346,974 Patented Oct. 17,1967 3,346,974 BULLDOZER AND BUCKET John A. Haynes, 14B Brown Ave.,Sylacauga, Ala. 35150 Filed Apr. 7, 1965, Ser. No. 446,284 16 Claims.(Cl. 37-1175) This invention relates to a bulldozer and bucket and moreparticularly to apparatus which shall be adapted for selective use as abulldozer or bucket.

An object of my invention is to provide a bulldozer and bucket whichshall be operable from a translatable frame such as a tractor,Caterpillar or the like without having to remove the blade when theapparatus is employed as a bucket.

Another object of my invention is to provide a bulldozer and bucket ofthe character designated in which the blade forms a rear wall for aforwardly opening bucket, thus reducing the number of parts as well asreducing the time required to change from a bulldozer to a bucket andvice versa.

A further object of my invention is to provide a bulldozer and bucket ofthe character designated in which the forward edge of the bottom walllimits rearward movement of the blade to thus absorb forces exertedagainst the lower end of the blade while the blade is in its lowermostposition for operation as a bulldozer blade.

A further object of my invention is to provide apparatus of thecharacter designated in which the blade is supported from side walls ofthe bucket by crank arms which are connected to a shaft-like member, thecrank arms and the shaft-like member lying in a common plane whichpasses through the lower end of the blade whereby upward force on theblade is exerted in this common plane.

A still further object of my invention is to provide a bulldozer andbucket construction of the character designated which shall be simple ofconstruction, economical of manufacture and one which may be mounted onvarious type translatable frames with a minimum of effort.

Heretofore in the art to which my invention relates, various types ofbulldozer blades and buckets have been proposed for handling materials.However, such apparatus has necessitated the removal of the bulldozerblade from the bucket while the bucket portion of the apparatus isemployed. In accordance with my present invention, the bulldozer bladeforms a rear wall of the bucket while the blade is in its rearmostposition. On the other hand, when the blade is moved to its forwardposition, it is adapted to move downwardly whereby the lower edge of theblade is positioned below the forward edge of the bottom of the bucket.The bottom of the bucket thus limits rearward movement of the blade andabsorbs forces exerted against the lower end of the blade. Improvedmeans is provided to move the blade selectively from a forward positionto a rearward position whereby the apparatus may be employed selectivelyas a bulldozer and bucket.

Apparatus embodying features of my invention is illustrated in theaccompanying drawings, forming a part of this application, in which:

FIG. 1 is a side elevational view, party broken away, showing thebulldozer and bucket unit mounted on a Caterpillar type tractor;

FIG. 2 is a front elevational view of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged sectional view taken generally along the line 3-3of FIG. 2;

FIG. 4 is a fragmental view corresponding to FIG. 3 but showing theblade moved to its rearmost position where it is employed as a rear wallfor the bucket;

FIG. 5 is a fragmental view, partly broken away, taken generally alongthe line 5-5 of FIG. 3;

FIG. 6 is an enlarged, sectional view taken generally along line 6-6 ofFIG. 5;

FIG. 7 is a frag-mental view taken generally along the line 7-7 of FIG.6;

FIG. 8 is a vertical sectional view corresponding to FIG. 3 but showinga modified form of my invention;

FIG. 9 is a fragmental view taken generally along the line 9-9 of FIG.8;

FIG. 10 is a fragmental view taken along the line 10-10 of FIG. 9 whilethe blade is in its forwardmost, lowered position;

FIG. 11 is a fragmental, sectional view taken along the line 10-10 ofFIG. 9 while the blade is in its forwardmost, raised position;

FIG. 12 is a fragmental, sectional view taken along the line 10-10 ofFIG. 9 while the blade is in its rearmost position to serve as a backwall for the bucket;

FIG. 13 is a fragmental, sectional view taken generally along the line13-13 of FIG. 9; and,

FIG. 14 is a fragmental view showing a modified form of my inventionwherein the blade is actuated by a lever arm which in turn isoperatively connected to a fluid pressure operated cylinder.

Referring now to the drawings for a better understanding of myinvention, I show a translatable frame 10 which may be in the form of aconventional type tractor, crawler type tractor, or the like. Mounted onthe translatable frame 10 by suitable linkage indicated generally at 11is a bulldozer blade and bucket unit indicated generally at 12. Thelinkage 11 is moved to selected positions relative to the translatableframe 10 by suitable fluid pressure operated cylinders 13 whereby theblade and bucket unit 12 may be raised or lowered to selected positionsfor use as a bulldozer blade or as a bucket. The blade and bucket unit12 comprises a pair of horizontally spaced side walls 14 which areconnected to each other at their lower ends by a bottom wall 16. Rearportions of the side walls 14 are connected to each other by transversemembers 17 and 18 which in turn are operatively connected to thetranslatable frame 10 by the members 11, as shown. The transversemembers 17 and 18 are connected to each other intermediate the endsthereof by a connecting member 19 which serves as a brace between thetransverse members 17 and 18 and for a purpose to be set forthhereinafter.

Mounted for pivotal movement between the side walls 14 is a blade 21.Mounted on and adapted for rotation relative to the blade 21 is anelongated shaft-like member 22. Suitable bearing members 23 are carriedby the rear surface of the blade 21 in position to receive the shaftlikemember 22, as shown in FIG. 5. Secured to each end of the elongatedshaft-like member 22 is a laterally projecting arm24; Secured to theupper end of each of the arms 24 is a horizontally extending member 26which is adapted for rotation in a suitable opening 27 provided in theadjacent side wall 14. The outer end of each member 26 is threaded forreceiving a nut 28 which retains the horizontal members 26 in assembledrelationship to the side walls 14. The upper portion of each arm 24,together with the horizontally extending member 26 thus define crankarms which are connected rigidly to the shaft-like member 22. Suitablerecesses 29 are provided at each end of the blade 21 whereby the crankarms are adapted for free rotation relative thereto. The recesses 29 aredefined by forwardly projecting arcuate members 31 whereby materialsengaged by the blade 21 do not pass through the recesses.

Formed integrally with the arm 24 is a depending member 32 which isadapted to extend alongside the rear side of the blade 21, as shown inFIGS. 3-5. Mounted for horizontal movement on the rear side of the blade21 is an elongated latch pin 33 which is adapted to engage the dependingmember 32, as shown in FIG. 5, while the blade is in its forwardposition. The latch pin 33 passes through a housing 34 which is mountedon the rear side of the blade 21, as shown. A spring abutment 36 iscarried by the pin 33 and a spring 37 surrounds the pin intermediate thespring abutment 36 and a side of the housing 34 whereby the spring urgesthe latch pin 33 toward the adjacent side wall 14 and into engagementwith the adjacent depending member 32. Pivotally connected to the latchpin 33 by a pivot pin 38 is an actuating rod 39 which passes throughsuitable bearing members 41 carried by the rear side of the blade 21whereby the rod 39 is adapted for axial movement. The other end of therod 39 is pivotally connected by a pivot pin 42 to a lever arm 43 whichin turn is pivotally mounted on a pin 44. A roller 46 is carried by thefree end of each of the arms 43 in position to engage a bearing surface47 carried by an elongated rack indicated generally at ,48. That is, therack 48 is provided with a bearing surface 47 at each side thereof whichmerges with an outwardly curved cam surface 49 which in turncommunicates with longitudinally extending bearing surfaces 51, as shownin FIG. 7.

Secured to the lower end of the rack 48 is a piston rod 52 of a fluidpressure operated cylinder 53. As shown in FIGS. and 6, the cylinder 53is mounted on the rear side of the blade 21 whereby the piston rod 52 isadapted to reciprocate the rack 48. The rack 48 is mounted for slidingmovement in suitable guide members 54 which are carried by the rear sideof the blade 21, as shown.

The teeth of the rack 48 mesh with a pinion 56 which is connected to theshaft-like member 22 by a lost motion connector which permits a limitedamount of initial movement of the pinion relative to the shaft-likemember 22. The lost motion connector is provided by providing arcuaterecesses 57 in the pinion 56 in position to receive outwardly projectingdetents 58 carried by the shaft-like member 22, as shown in FIG. 6. Thatis, the recesses 57 permit a limited amount of angular movement of thedetents 58 before engagement wtih the ends of the recesses 57.

Initial movement of the piston rod 52 in a downward direction causes therack 48 to move downward whereupon the detents 58 rotate relative to therecesses 57. This initial movement of the rack 48 causes the rollers 46to engage the cam surfaces 49 and thus move outwardly whereupon theyride along the bearing surfaces 51. As the rollers 46 are movedoutwardly by the cam surfaces 49, each arm 43 is pivoted about its pivotpin 44 whereupon the actuating rods 39 and the latch pins '33 carriedthereby are moved inwardly to thus disengage the depending members 32.After the latch pins 33 have disengaged the depending members 32, thecrank arms at the ends of the shaft-like member 22 are free to rotaterelative to the openings 29.

Continued movement of the rack 48 in a downward direction after thedepending members 32 have been freed causes this pinion 56 .to rotate inthe direction of the arrow 59 to thereby impart rotation to theshaft-like member 22 about the horizontal members 26 whereupon the arms24 and the blade 21 move from the solid line position to the dotted lineposition shown in FIG. 3. As the blade 21 moves from the solid lineposition to the dotted line position, it is elevated from a positionbelow the forward edge of the bottom wall 16 to a position above thebottom wall 16. While the blade 21 is in the lowered, solid lineposition shown in FIG. 3, the forward edge of the bottom wall 16 limitsrearward movement of the lower end of the blade 21 whereby thehorizontal forces exerted against the lower end of the blade 21 areabsorbed by the forward edge of the bottom wall 16. The lower end of theblade 21 carries a suitable cutter element 61, as shown. Also, while theblade 21 is in the lowered or solid line position shown in FIG. 3, theshaft 22 and the horizontal member 26 lie in a common plane which alsoextends through the lower end of the blade 21. Accordingly, any upwardforces exerted against the blade 21 are transmitted in this common planewhich extends through the shaft 22 and the horizontal member 26 wherebythere is no pivotal movement of the crank arms defined by the arms 24and the horizontal members 26. i

The plate 21 is moved from the dotted line position shown in FIG. 3 tothe position shown in FIG. 4 by a piston rod 62 which is connected tothe blade 21 by a suitable pivot pin 63. The piston rod 62 is actuatedby a fluid pressure operated cylinder 64 which is pivotally connected tothe member 19 by a pivot pin 66. Upon movement of the blade 21 to theraised or dotted line position shown in FIG. 3, the blade is then freeto move rearwardly to the position shown in FIG. 4. That is, after theblade 21 is raised to the dotted line position shown in FIG. 3, thecylinder. 64 is actuated to move the piston rod 62 inwardly of thecylinder 64, thus to move to the rearmost position as shown in FIG. 4 tothereby serve as a rear wall for a bucket unit. Accordingly, the blade21 may be moved selectively from the solid line position shown in FIG. 3to the position shown in FIG. 4 whereby the unit may be employedselectively as a bulldozer blade and as a bucket.

From the foregoing description, the operation of my improved apparatusshown in FIGS. 1-7 will be readily understood. To use the unit as abulldozer blade, the blade 21 is moved to the solid line position shownin FIG. 3 whereupon the lower edge thereof extends below the forwardedge of the bottom wall 16. Accordingly, upon forward movement of theunit, the forward edge of the bottom wall absorbs forces exerted in ahorizontal direction against the lower end of the blade. The blade 21 isheld against vertical movement due to the fact that the shaft 22 and thehorizontal member 26 extend in a common plane which passes through thelower end of the blade thus preventing rotation of the shaft-like memberrelative to the member 26.

To employ the unit as a bucket, the piston 53 is energized whereupon thepiston rod 52 and rack 48are moved downwardly. Initial downwardmovementof the rack 48 causes the roller 46 to engage the cam surfaces49 and thus move outwardly into engagement with the bearing surfaces 51.This outward movement of the rollers 46 causes the latch pins 33 torelease the depending members 32 whereupon the arms 24 are free torotate relative to the blade 21. Continued downward movement of the rack48 imparts rotary motion to the pinion 56 due to engagement of thedetents 58 with the recesses 57. As the pinion 56 rotates in thedirection of the arrow 59, the

arm 24 and the blade 21 move from the solid line position to the dottedline position shown in FIG. 3. The fluid pressure operated cylinder 64is then energized whereupon the piston rod 62 moves the blade 21 fromthe dotted line position shown in FIG. 3 to the position shown in FIG.4. In the position shown in FIG. 4, the blade 21 serves as a rear wallfor a bucket whereby the apparatus may be employed to convey materialsfrom place to place.

In FIGS. 8-13 of the drawings, I show a modified form of my invention inwhich a blade 21 is adapted for pivotal movement between a pair of sidewalls 14. A bottom wall 16 extends between the lower edges of the sidewalls 14 and is rigidly secured thereto whereby the side walls 14 areheld in horizontally spaced relation to each other as the side walls 14are held in spaced relation to each other by bottom wall 16 in theapparatus shown in FIGS. 1-7. The rear ends of the side walls 14- areconnected to each other by transverse members 17 and 18 Also, thetransverse members 17 and 18 are connected to each other by a bracemember 19 The lower end of the blade 21 is provided with a cutting edge61*, as shown in FIG. 8. The transverse member 17 and 18 also carryrearwardly extending brackets whereby the unit may be pivotally attachedto a suitable linkage, such as the linkage 11 shown in FIG. 1.

Secured to each end of the blade 21 adjacent the upper end thereof is anoutwardly extending bracket 67 having a generally rectangular portion 68at the outer end thereof which extends parallel to the blade 21*. Eachrectangular portion 68 passes through an opening provided in the upperportion of the adjacent side wall 14*. Each opening in the side wall 14is provided with a vertically extending lower portion 69 which isadapted to receive the rectangular portion 68 of the bracket 67 with asnug fit, as shown in FIG. 10. The upper portion of the opening througheach side wall 14 is provided with diagonally extending portions 71 and72. The diagonal portion of the opening 71 is provided with sideportions 73 and 74 while the diagonal portion 72 communicates at oneside with the depending opening 69 and is provided with a side wall 76at the other side thereof. Accordingly, the rectangular member 68 isadapted to move from the lower position shown in FIGS. 8 and 10 to anelevated position shown in FIG. 11 whereby the lower end of blade 21 ismoved from a lower position beneath the forward edge of the bottom wall16 to a position above the forward edge of the bottom wall 16*.Continued pivotal movement of the plate 21 relative to the side walls 14causes the rectangular member 68 to move from the position shown in FIG.11 to the position shown in FIG. 12 whereby it engages the walls 73 and76 of the opening through the side wall 14.

Secured to the bracket 67 adjacent each side of the adjacent side wall14 is a disc-like member 77 which completely covers the opening throughthe side walls 14 to thereby prevent the ingress of foreign materials,such as dirt and the like inwardly of the opening. The disc-like members77 are secured to the bracket 67 by suitable means, such as by weldingor the like.

Pivotally connected to the lower portion of the blade 21 by a pivot pin63 is a piston rod 62 of a fluid pressure operated cylinder 64 Thecylinder 64 is pivotally connected to the member 19 by a suitable pivotpin 66 whereby the blade 21 is adapted to move from the solid lineposition shown in FIG. 8 to the dotted line position.

From the foregoing, the operation of the apparatus shown in FIGS. 813will be readily understood. To operate the unit as a bulldozer blade,the blade is moved to the solid line position shown in FIG. 8 wherebythe lower edge of the blade extends forwardly of and below the forwardedge ofthe bottom wall 16*. The bottom wall 16 thus absorbs the forcesexerted against the lower end of the blade 21 Since the piston rod 62extends downwardly and forwardly relative to the blade, the piston rodwould prevent upward movement of the blade while it is employed as abulldozer blade. However, suitable means may be employed to lock theblade 21 in its lowermost position other than the use of the piston rod62 and the fluid pressure operated cylinder 64*.

To use the apparatus shown in FIGS 8l3 as a bucket, the fiuid pressureoperated cylinder 64 is actuated to move the blade to the dotted lineposition shown in FIG. 8. Initial movement of the blade 21* from thesolid line position shown in FIG. 8 causes the blade and the rectangularportion 68 of the bracket 67 to move to the position shown in FIG. 11.Continued rearward movement of the blade 21* by the piston rod 62 causesthe blade to move to the dotted line position shown in FIG. 8 whereuponthe rectangular portion 68 moves to the position shown in FIG. 12. Therectangular portion 68 thus engages the sides 73 and 76 of the openingthrough the side walls 14 whereby the blade is held in the dotted lineposition.

Referring now to FIG. 14 of the drawings, I show another modified formof my invention in which a lever arm 78 is secured rigidly to ashaft-like member 22. That is, the shaft-like member 22 would be mountedfor rotation on the blade 21 as set forth hereinabove relative to theapparatus shown in FIGS 1-7. The outer end of the arm 78 is pivotallyconnected to the upper end of a piston rod 79 of a fluid pressureoperated cylinder 81. The cylinder 81 is pivotally connected to the rearside of the blade 21 by a pivot pin 82 which passes through a suitablebracket 83 carried by the rear side of the blade 21. The blade 21 may belocked in lowered or raised position by suitable means, not shown.

From the foregoing, it will be seen that I have devised an improvedbulldozer and bucket unit which may be converted selectively for use asa bulldozer blade or bucket with aminimum of etfort. By providing ablade which is adapted to extend forwardly of and below the forward edgeof the bottom wall of the bucket, rearward move ment of the lower end ofthe blade is limited by the bottom wall and at the same time the bottomwall absorbs the forces exerted against the lower end of the blade.Also, by providing a blade which may be raised and then pivotedrearwardly to a position adjacent the rear ends of the side walls of theunit, the apparatus is adapted for use as a bucket without having toremove the blade from the side walls in any manner. Furthermore, byproviding a bulldozer and bucket unit which is adapted for operation byfluid under pressure, the er tire apparatus may be actuated by theoperator who rides on a translatable frame without the necessity of theoperator leaving the translatable frame.

While I have shown my invention in several forms, it will be obvious tothose skilled in the art that it is not so limited but is susceptible ofvarious other changes and modifications without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are specifically set forth in the appendedclaims.

What I clairn is:

1. In a bulldozer and bucket unit adapated to be supported on atranslatable frame,

(a) a pair of horizontally spaced side walls,

(b) a bottom wall extending between and connected to lower portions ofsaid side walls,

(c) a blade pivotally supported between said side walls and adapted forpivotal movement to a first position adjacent the front edge of saidbottom wall in position to operate as a buldozer blade and to a secondposition adjacent the rear edge of said bottom wall in position todefine with said side walls and said bottom wall a forwardly openingbucket,

(d) said blade being adapted to move selectively to a lower positionwith the lower edge thereof below the front edge of said bottom wall andto an upper position with the lower edge thereof above said front edgeof said bottom wall,

(e) means to move said blade selectively to said lower position and saidupper position while said blade is in said first position adjacent saidfront edge of the bottom wall, and

(f) means to move said blade while in raised position selectively tosaid first position and said second position.

2. In a bulldozer and bucket unit adapted to be supported on atranslatable frame as defined in claim 1 in which rear portions of saidside walls are connected to each other by transverse members which inturn are aperatively connected to the translatable frame.

3. In a bulldozer and bucket unit adapted to be supported on atranslatable frame as defined in claim 1 in which the blade is movedselectively to said first position and said second position by a fiuidpressure operated cylinder unit operatively connected at one end to therear side of said blade.

4. In a bulldozer and bucket unit as defined in claim 1 in which theblade is pivotally supported between said side walls adjacent the upperfront edges of said side Walls.

5. In a bulldozer and bucket unit as defined in claim 1 7 in which theblade is held in said lower position by releasable latch means.

6. In a bulldozer and bucket unit as defined in claim 1 in which theblade is pivotally supported between said.

side walls by means comprising:

(a) an elongated shaft like member mounted for rotation on said bladeand adapted to support said blade,

(b) crank-like arm members rotatably supported by said side Walls andconnected to the ends of said shaft-like member in position to move saidblade selectively to said lower position and said upper position uponrotation of said shaft-like member in opposite directions, and

(c) means to rotate said shaft-like member.

7. In a bulldozer and bucket unit as defined in claim 6 in which themeans to rotate the shaft comprises a lever arm connected at one end tosaid shaft, and power actuating means operatively connected to the otherend of said lever arm.

8. In a bulldozer and bucket unit as defined in claim 6 in which thecrank arm and the shaft-like member extend in a common plane which alsoextends through the lower end of said blade while said blade is in saidlower position.

9. In a bulldozer and bucket unit as defined in claim 6 in which themeans to rotate said shaft comprises:

(a) a rack carried by and adapted for movement relative to the rear sideof said blade,

(b) a pinion carried by said shaft-like member is in position to engagesaid rack, and

(c) means to move said rack to rotate said pinion.

10. In a bulldozer and bucket unit as defined in claim 9 in which saidmeans to move said rack includes a fluid pressure operated cylinderwhich is carried by the rear side of said blade and operativelyconnected to said rack.

11. In a bulldozer and bucket unit as defined in claim 9 in which eachcrank arm comprises:

(a) an elongated arm connected to the adjacent end of said shaft, and

(b) means pivotally connecting one end of said elongated arm to saidside wall adjacent thereto.

12. In a bulldozer and bucket unit as defined in claim 11 in which saidelongated arm is connected to the end of said shaft intermediate theends of said elongated arm whereby the other end of said elongated armopposite said one end thereof which is pivotally connected to said sideside wall extends beyond said shaft, and a releasable latch member iscarried by said blade in position to engage said other end.

13. In a bulldozer and bucket unit as defined in claim 12 in which thereleasable latch member comprises:

(a) an elongated latch adapted for movement relative to, said blade, (b)spring means urging said latch into engagement with said other end ofsaid elongated arm, and (c) an actuating member carried by said rack inposition to move said elongated latch out of engagement with said otherend of the elongated arm upon rotation of said pinion in one direction.

14. In a bulldozer and bucket unit as defined in claim 13 in which theactuating member comprises a cam member carried by said rack in positionto engage said latch.

15. In a bulldozer and bucket unit as defined in claim 12 in which alost motion connection is provided between said pinion and said shaftwhereby initial movement of said pinion releases said releasable latchmember.

16. In a bulldozer and bucket unit as defined in claim 1 in which theblade is pivotally supported between said side walls by meanscomprising:

(a) support members carried by opposite ends of said blade andprojecting outwardly therefrom,

(b) there being recesses in the upper forward portions of said sidewallsin position to receive said support members,

(c) said recesses having a downwardly extending portion in position toreceive said support members while said blade is in said first positionadjacent said front edge of the bottom wall, and

(d) said recess having laterally extending portions in position toengage and support said support members while said blade is pivotedrearwardly away from saidfirst position.

References Cited UNITED STATES PATENTS 2,852,869 9/1958 Beyerstedt37l17.5 3,092,920 6/1963 Benno 37-1175 3,122,248 2/1964 Campbell et al.37-1175 X 3,250,028 5/1966 Hunger et al. 37-1175 ABRAHAM G. STONE,Primary Examiner.

R. L. HOLLISTER, Assistant Examiner.

1. IN A BULLDOZER AND BUCKET UNIT ADAPTED TO BE SUPPORTED ON ATRANSLATABLE FRAME, (A) A PAIR OF HORIZONTALLY SPACED SIDE WALLS, (B) ABOTTOM WALL EXTENDING BETWEEN AND CONNECTED TO LOWER PORTIONS OF SAIDSIDE WALLS, (C) A BLADE PIVOTALLY SUPPORTED BETWEEN SAID SIDE WALLS ANDADAPTED FOR PIVOTAL MOVEMENT OF A FIRST POSITION ADJACENT THE FRONT EDGEOF SAID BOTTOM WALL IN POSITION TO OPERATE AS A BULDOZER BLADE AND TO ASECOND POSITION ADJACENT THE REAR EDGE OF SAID BOTTOM WALL IN POSITIONTO DEFINE WITH SAID SIDE WALLS AND SAID BOTTOM WALL A FORWARDLY OPENINGBUCKET, (D) SAID BLADE BEING ADAPTED TO MOVE SELECTIVELY TO A LOWERPOSITION WITH THE LOWER EDGE THEREOF BELOW THE FRONT EDGE OF SAID BOTTOMWALL AND TO AN UPPER POSITION WITH THE LOWER EDGE THEREOF ABOVE SAIDFRONT EDGE OF SAID BOTTOM WALL, (E) MEANS TO MOVE SAID BLADE SELECTIVELYTO SAID LOWER POSITION AND SAID UPPER POSITION WHILE SAID BLADE IS INSAID FIRST POSITION ADJACENT SAID FRONT EDGE OF THE BOTTOM WALL, AND (F)MEANS TO MOVE SAID BLADE WHILE IN RAISED POSITION SELECTIVELY TO SAIDFIRST POSITION AND SAID SECOND POSITION.